A further empirical analysis in [1]} made such explanations implausible, if not outright impossible.
The experiments used a popular class of algorithms known as kernel machines, which are mathematically predictors of the form
\( f({\mathbf {x}}) = \sum _{i=1}^n \alpha _i K({\mathbf {x}}_i,x), ~~\alpha _i \in {\mathbb {R}}\) 
